Borate-treated plywood in Florida: what it is and what to specify
Borate treatment is popular in Florida because termites are a real cost here. It is also easy to misuse, because it behaves very differently from the pressure-treated wood most people picture.
What borate treatment is
Borate-treated plywood has a boron-based preservative worked into the wood. It protects against termites, wood-boring beetles and decay fungi. It is commonly used for framing and sheathing inside the building envelope.
The catch: borate washes out
Borate dissolves in water. That makes it a good fit for wood that stays dry or is protected from rain, and a poor fit for wood exposed to weather or sitting in soil. It is generally intended for interior and protected uses, not ground contact. For exposed or ground-contact parts, you want a different preservative system, not borate.
| Use | Borate plywood a good fit? |
|---|---|
| Interior sheathing or subfloor, kept dry | Generally yes |
| Wall or roof sheathing that is covered quickly | Possibly. Keep it protected from rain during construction. |
| Exposed to rain or splash | Not on its own |
| Touching soil or concrete that stays wet | No. Use a ground-contact rated product. |
Borate is not the same as fire-retardant plywood
Fire-retardant-treated (FRT) plywood is a different product made for a different reason. If a plan calls for FRT, borate plywood is not a substitute.
What to put in your quote request
Include thickness, grade, quantity, what it will be used for, and the word “borate” so the yard does not quote untreated or pressure-treated panels. Ask how the treatment is certified and whether the product is in stock, since borate panels are often a special order.
Questions to ask the yard
- Which preservative and which use category is it rated for?
- Is it in stock, or what is the lead time?
- What should I do to keep it dry on site until it is covered?
- Is there a data sheet I can show my inspector or customer?
Want prices from South Florida yards?
Send your list. We ask several yards for current pricing and send you the comparison. Free for buyers.
Get my quotes